Both for places where a decorative effect and a mood-producing effect are desired, such as hotel, restaurant, various kinds of club and theatre, and for private dwelling and office, especially in front hall, drawing room, etc. thereof, said decorative and mood-producing effects are required for lighting, in addition to the illuminative effect proper. As the lighting suitable for the above-mentioned places, a combination, for example, of chandeliers, louvers, mini-lamps and special globes is well known. However, such prior art lighting principally relies upon the light intensity of individual lamps and is designed rather as a purely illuminative means. Furthermore, such well known lighting systems produce decorative effect by arranging independent modular light emitting elements or individual lamps in accordance with a predetermined pattern defined in a space by combining these light emitting elements or lamps with separately provided decorative objects.
A lighting device has already been proposed which, although useful also for illuminative purpose, is rather suitable for the places where the decorative and mood-producing effects are important rather than the light intensity. Such adevice is disclosed, for example, in Unexamined Disclosure of Japanese Utility Model Application No. 54-159778 in which a modular lighting structure comprises a plurality of minilamps arranged at suitable intervals and electrically connected to one another within a suitable length of inflexible, transparent pipe and these modular lighting structures each serving as a lamp bulb are assembled according to a desired pattern. Unexamined Disclosure of Japanese Utility Model Application No. 54-11086 discloses another proposal by which a plurality of modular lighting tubes, each comprising a plurality of mini-lamps are arranged within a transparent pipe previously curved into a ring-shape, are electro-mechanically connected to a lamp-cassette. Thus, the assembly of modular lighting structures each comprising the ring of a large circumferential dimension containing therein a plurality of mini-lamps is realized which is excellent not only in its illuminative effect but also in its decorative effect, produced when the light is turned on.
However, such lighting devices of prior art disclosed in both the above-identified applications are inconvenient in that the pipes are inflexible and therefore have no freedom of their configuration changes. More specifically, these pipes are prefabricated in predetermined configurations and lengths depending upon the particular places of their installation, so that the products of the correspondingly particular configurations and dimensions must be ordered and fabricated.
To avoid such inconvenience, an improved modular lighting tube for lighting device has been proposed, for example, by Unexamined Disclosure of Japanese Utility Model Application No. 54-89082, according to which a plurality of mini-lamps are arranged within a flexible, long tube of transparent synthetic resin. In this proposal, respective pairs of adjacent mini-lamps are electrically connected to one another by elastic conductors so that, even when said elastic conductors constituting the circuit wires for the interior mini-lamps are subjected to a tension as the tube itself is bent, said elastic conductors are effectively extended to avoid a stress concentration which otherwise would result in a wire breakage.
Nevertheless, all of these disclosures are principally based on the illuminative function of the independent modular lighting structures and have no suggestion of continuously connecting the modular lighting structures, each relatively long, into a single but longer lighting structure. Even if it is desired to form such a long lighting device from a plurality of modular lighting structures, the respective adjacent modular lighting structures should be connected by separately provided intermediate connector members to one another, or these modular lighting structures should be merely arranged in a row and put on light so that they appear as if they are continuous. Any way, the portions destined for connection would be occupied by the intermediate connector members quite different from the modular lighting structures in their configuration, material and color and the electrical circuit wires associated with these intermediate connector members, or would be void, so that the modular lighting structures really would be intermittently arranged. Such lighting device consisting of thus intermittently arranged modular lighting structures would be undersirable with respect to its decorative effect.
The continuous arrangement as mentioned above necessarily results in increase of impressed voltage to obtain the minimum limit of power when the mini-lamps contained therein are connected in series as a whole, or can not be compatible with the commerical power supply unless larger bulbs are used, when connected in parallel. In the latter case, the arrangement would be suitable for the illuminative purpose rather than for the decorative purpose.
Furthermore, the modular lighting structures of prior art must, without exception, be provided on opposite ends with electrodes and the exposed connecting cords would spoil the aesthetic effect when it is desired to use the arrangement for the decorative purpose, for example, in a chandelier.